396 AMAKANTHACEAE 



oblong or elliptic, 1.5-6 cm. long, obtuse, commonly mucronate, entire, sessile or some- 

 what petioled : spikes dull straw-colored, 6-12 mm. long, sessile, at maturity resembling 

 the flower-clusters of Ephedra, leaving a conspicuous scar when detached : bracts ovate, 

 keeled : calyx longer than the bracts : sepals rigid, ovate, acute and slightly awn-tipped, 

 usually 5-nerved, glabrous : staminodia longer than the filaments, cleft or lacerate at the tip. 

 In sand, peninsular Florida and tropical America. 



4. Alternanthera philoxeroides (Mart.) Griseb. Plants glabrous or nearly so. 

 Stems or their branches prostrate or decumbent, freely creeping, the ascending portion often 

 1-5 dm. long, the upper internodes often a little hairy : leaf -blades somewhat fleshy, linear 

 to linear-oblanceolate, 2-10 cm. long, usually acute or mucronulate, entire, narrowed to the 

 sessile base : spikes subglobose or cylindric, 'long-peduncled, silvery white : peduncles 2-7 

 cm. long, glabrous or pubescent in lines : sepals 5-6 mm. long, glabrous, unequal, 4-nerved, 

 lanceolate, acute, firm : staminodia narrow, usually entire. 



In waste places, South Carolina to Florida and Louisiana. Also in tropical America. 



5. Alternanthera Moquinii Webb. Plants suggesting broad -leaved species ofAllionia. 

 Foliage glabrous or glabrate : stems erect or ascending, 3-8 dm. tall, sparingly forked : 

 leaves about as long as the internodes ; blades broadly ovate, 4-8 cm. long, acute or slightly 

 acuminate, entire, abruptly narrowed or truncate at the base, short-petioled : spikes si ender- 

 peduncled, ovoid, less than \ cm. long : peduncles shorter than the leaves : sepals 3-3. 5 

 mm. long, glabrous, mainly lanceolate, acute, surpassing the ovate, scarious-margined 

 acuminate bracts : staminodia surpassing the anthers and the very short filaments, fringed 

 at the apex : utricle included. 



In sand, Key West, Florida. Also in tropical America. 



6. Alternanthera Floridana (Chapm. ) Small. Plants slender. Pubescence minute, 

 appressed : stems erect, 6-14 dm. tall, forking, the internodes elongated : leaves much shorter 

 than the internodes ; blades lanceolate to elliptic, 1.5-3 cm. long, acute or acuminate, 

 entire, short-petioled or nearly sessile : spikes ovoid, about 1 cm. long, silvery white : 

 peduncles conspicuously elongated, many times longer than the leaves : sepals about 4 mm. 

 long, minutely pubescent, lanceolate or one of them broader, all acute, surpassing the 

 bracts : staminodia longer than the narrowly elongated filaments : utricle with a toothed 

 crown. [Telanthera Floridana Chapm.] 



In sand, peninsular Florida and the Keys. 



7. Alternanthera Brasiliana (L.) Kuntze. Plants stoutish. Pubescence compara- 

 tively long and coarse : stems erect, 0.5-2 m. tall, more or less forked, pubescent with as- 

 cending or spreading hairs : leaves commonly as long as the rather short internodes ; blades 

 lanceolate or oblong-lanceolate, 3-10 cm. long, acuminate, entire, cuneate or somewhat 

 rounded at the base, short-petioled: spikes slender-peduncled, ovoid to cylindric, 1-2.5 

 cm. long: sepals 4-4.5 mm. long, lanceolate or oblong-lanceolate, acute, finely pubescent : 

 anthers nearly sessile, or filaments very short : staminodia much surpassing the anthers : 

 utricle with an entire crown. 



In sand, peninsular Florida and tropical America. 



9. CLADOTHRIX Nutt. 



Annual or perennial, diffusely branched herbs. Foliage pubescent with stellate hairs. 

 Leaves mainly opposite : blades entire or merely undulate, short-petioled. Flowers per- 

 fect, subtended by 3 bracts, solitary or clustered in the axils. Sepals 5, equal, pubescent, 

 thin. Hypanthium small or obsolete. Stamens 5, hypogynous : filaments united at their 

 bases : anthers 1-celled. Ovary 1-celled, subglobose : style short : stigma capitate or 2- 

 lobed. Ovule solitary. Utricle subglobose, indehiscent. 



Annual : stems or branches mostly prostrate or procumbent. 1. C. lanuginosa. 



Perennial : stems or branches erect or ascending. 2. C. suffruticosa. 



1. Cladothrix lanuginosa Nutt. Annual, lanuginose. Stems branched at the base, 

 the branches procumbent or prostrate, 1-6 dm. long, forking, terete : leaves sometimes in 

 3' s at the joints, 2 smaller than the third ; blades suborbicular, ovate or rhombic-ovate, 

 obtuse or eraarginate at the apex, entire, 0.5-2 cm. long, rather prominently nerved 

 beneath, more or less abruptly contracted and often oblique at the base : flowers usually in 

 pairs : bractlets obtuse, pubescent : sepals twice as long as the bractlets, narrower, obtuse, 

 glabrousj 1-nerved : utricle glabrous, included in the calyx. 



In dry soil, Kansas to Texas, Arizona and Mexico. Spring to fall. 



2. Cladothrix suffruticosa (Torr. ) S. Wats. Perennial, lanuginose. Stems erect 

 or ascending, several from a woody base, forking, 1-1.5 dm. long, the branches ascending : 



